Hello @shoki, welcome to the QuickSight community!
After a quick look into this it seems like you may need to include the IamArn for the IAM user or IAM role you are using. How are you creating the users in IAM? Depending on how the users are set up, some of the other parameters may be required for the IAM authentication and creation.
Thank yout for replying for my quiestion @DylanM !
I did not create ima user or ima role, but create ima identity center user.
When QuickSight is integrated with IAM Identity Center, can I use the RegisterUser API to add users?
Can I specify IAM_IDENTITY_CENTER for the identityType when creating it?